1. Field of the Invention
The present invention relates to techniques of abating so-called “burn-in” in an image display apparatus supporting input signals of multiple types.
2. Description of Related Art
In a flat-panel image display apparatus (flat-panel display) of, for example, a liquid crystal or plasma type, when a same still image is displayed for a long time, so-called “burn-in” occurs. The “burn-in” refers to a phenomenon in which deterioration (reduction in emission luminance) of a part of a screen advances thereby allowing image trails (image lags) to be visible, and the phenomenon tends to appear at, for example, an edge portion of a still image.
Japanese Unexamined Patent Laid-Open No. 4-286275 and No. 5-150729 propose methods of abating the “burn-in” by reducing the luminance level upon detecting a predetermined time of display of still images.
In recent years, image display apparatuses are introduced that support ordinary TV signals and other input signals of various types, such as PC input signals input from PCs (personal computers) and DSC input signals input from DSCs (digital still cameras).
In the case of adaptation of the conventional techniques to an image display apparatus of the above-described type, depending on the type of an input signal (namely, an input mode (port) or image characteristics), a case can potentially occur in which appropriate display is not performed. Particularly, with the luminance level uniformly decreased as in the conventional case, when displaying PC input signals or still images of high luminance and high contrast, problems occur in that the screen is darkened overall, thereby causing deterioration in visibility and operability.